A cosmic double helix in the archetypical quasar 3C273

Finding direct evidence for plasma instability in extragalactic jets is crucial for understanding the nature of relativistic outflows from active galactic nuclei. Our radio interferometric observations of the quasar 3C273 made with the orbiting radio telescope, HALCA, and an array of ground telescopes have yielded an image in which the emission across the jet is resolved, revealing two threadlike patterns that form a double helix inside the jet. This double helical structure is consistent with a Kelvin-Helmholtz instability, and at least five different instability modes can be identified and modeled by a light jet with a Lorentz factor of 2 and Mach number of 3.5. The model reproduces in detail the internal structure of the jet on scales of up to 30 milli-arc seconds ( approximately 300 parsecs) and is consistent with the general morphology of the jet on scales of up to 1 kiloparsec.     

Electron Plasma Oscillations Associated with Type III Radio Bursts

Plasma wave electric field measurements with the solar orbiting Helios spacecraft have shown that intense (approximately 10 millivolts per meter) electron plasma oscillations occur in association with type III solar radio bursts. These observations confirm the basic mechanism, proposed in 1958, that type III radio emissions are produced by intense electron plasma oscillations excited in the solor corona by electrons ejected from a solar flare.     

Spacelab-2 plasma depletion experiments for ionospheric and radio astronomical studies

The Spacelab-2 Plasma Depletion Experiments were a series of studies to examine shuttle-induced perturbations in the ionosphere and their application to ground-based radio astronomy. The space shuttle Challenger fired its orbital maneuvering subsystem engines on 30 July and 5 August 1985, releasing large amounts of exhaust molecules (water, hydrogen, and carbon dioxide) that caused the electrons and ions in Earth's upper atmosphere to chemically recombine, thereby creating so-called "ionospheric holes." Two burns conducted over New England produced ionospheric peak depletions ranging from 25 to 50 percent, affected the ionosphere over a 200-kilometer altitude range, and covered 1 degrees to 2 degrees of latitude. Optical emissions associated with the hole spanned an area of several hundred thousand square kilometers. A third burn was conducted over a low-frequency radio observatory in Hobart, Australia, to create an "artificial window" for ground-based observations at frequencies normally below the natural ionospheric cutoff (penetration) frequency. The Hobart experiment succeeded in making high-resolution observations at 1.7 megahertz through the induced ionospheric hole.     

Earth-Based Radio Tracking of the Galileo Probe for Jupiter Wind Estimation

Although the Galileo probe was designed to communicate only to the orbiter, the probe radio signal was detected at two Earth-based radio observatories where the signal was a billion times weaker. The measured signal frequency was used to derive a vertical profile of the jovian zonal wind speed. Due to the mission geometry, the Earth-based wind estimates are less sensitive to descent trajectory errors than estimates based on probe-orbiter Doppler measurements. The two estimates of wind profiles agree qualitatively; both show high wind speeds at all depths sampled.     

Measurements of turbulence in the venus atmosphere deduced from pioneer venus multiprobe radio scintillations

The 2.3-gigahertz log-amplitude fluctuations observed in the radio links of the Pioneer Venus entry probes during Venus encounter have been used to study turbulence in the Venus atmosphere. The deduced estimates of the upper bound of structure constant c(n) of the refractive index fluctuations (c(n) less, similar 4 x 10(-8) cm(-(1/3))) are inconsistent with similar entry probe measurements by Veneras 4 to 8 but are consistent with the radio occultation measurements by flyby (Mariners 5 and 10) and orbiting (Venerat 9) spacecraft. The Pioneer Venus measurements therefore provide a resolution of the long-standing order of magnitude discrepancy between these earlier measurements of c(n).     

Apollo 16 Geochemical X-ray Fluorescence Experiment: Preliminary Report

The lunar surface was mapped with respect to magnesium, aluminum, and silicon as aluminum/ silicon and magnesium/ silicon intensity ratios along the projected ground tracks swept out by the orbiting Apollo 16 spacecraft. The results confirm the observations made during the Apollo 15 flight and provide new data for a number of features not covered before. The data are consistent with the idea that the moon has a widespread differentiated crust (the highlands). The aluminum/ silicon and magnesium/ silicon concentration ratios correspond to those for anorthositic gabbros through gabbroic anorthosites or feldspathic basalts. The x-ray results suggest the occurrence of this premare crust or material similar to it at the Descartes landing site.     

Precision Geodesy via Radio Interferometry

Very-long-baseline interferometry experiments, involving observations of extragalactic radio sources, were performed in 1969 to determine the vector separations between antenna sites in Massachusetts and West Virginia. The 845.130-kilometer baseline was estimated from two separate experiments. The results agreed with each other to within 2 meters in all three components and with a special geodetic survey to within 2 meters in length; the differences in baseline direction as determined by the survey and by interferometry corresponded to discrepancies of about 5 meters. The experiments also yielded positions for nine extragalactic radio sources, most to within 1 arc second, and allowed the hydrogen maser clocks at the two sites to be synchronized a posteriori with an uncertainty of only a few nanoseconds.     

Confirmation of Earth-Mass Planets Orbiting the Millisecond Pulsar PSR B1257 + 12

The discovery of two Earth-mass planets orbiting an old ( approximately 10(9) years), rapidly spinning neutron star, the 6.2-millisecond radio pulsar PSR B1257+12, was announced in early 1992. It was soon pointed out that the approximately 3:2 ratio of the planets' orbital periods should lead to accurately predictable and possibly measurable gravitational perturbations of their orbits. The unambiguous detection of this effect, after 3 years of systematic timing observations of PSR B1257+12 with the 305-meter Arecibo radiotelescope, as well as the discovery of another, moon-mass object in orbit around the pulsar, constitutes irrefutable evidence that the first planetary system around a star other than the sun has been identified.     

地面自动气象站观测数据文件的质量控制

通过分析地面自动气象站观测数据文件A文件、分钟观测数据文件J文件中出现的缺测记录和疑误记录,并结合工作实际,提出了合理解决方法,最大限度地减少了观测数据文件中的缺测记录和疑误记录,保证了气象资料的完整性、连续性和准确性,从而实现地面气象观测资料的质量控制。     

1981N1: A Neptune Arc?

An object in the vicinity of Neptune detected in 1981 by simultaneous stellar occultation measurements at observatories near Tucson, Arizona, was interpreted as a new Neptune satellite. A reinterpretation suggests that it may have instead been a Neptune arc similar to one observed in 1984. The 1981 object, however, did not occult the star during simultaneous observations at Flagstaff, Arizona. This result constrains possible arc geometries.     

Detection of the intrinsic size of Sagittarius A* through closure amplitude imaging

We have detected the intrinsic size of Sagittarius A*, the Galactic center radio source associated with a supermassive black hole, showing that the short-wavelength radio emission arises from very near the event horizon of the black hole. Radio observations with the Very Long Baseline Array show that the source has a size of 24 +/- 2 Schwarzschild radii at 7-millimeter wavelength. In one of eight 7-millimeter epochs, we also detected an increase in the intrinsic size of 60(-17)(+25)%. These observations place a lower limit to the mass density of Sagittarius A* of 1.4 x 10(4) solar masses per cubic astronomical unit.     

泽当城市草面温度变化规律初探

[目的]研究泽当城市草面温度的变化规律.[方法]通过对泽当国家气象观测站2011年12月～2012年11月草面温度和地表温度进行对比分析,考察泽当城市草面温度的变化规律.[结果]在各种典型天气条件下,苹面温度和地面温度差值日变化趋势较为一致,只是二者交替出现的时间略有差异,晴天出现交替出现时间最早;二者变化最为剧烈的时候出现在午前和午后;日出和日落前后是草面温度和地面温度一日中的交替时次;冬春白天草面温度要高于地面温度、夏天除早晨8：00 ～9：00二者基本接近外,地表温度始终高于草面温度,草面温度高于地表温度出现在秋季上午9：00之前,10：00之后地表温度明显高于草面温度.[结论]该方法为探讨泽当城市草面温度的变化规律提供了依据.     

The mass of dwarf planet Eris

The discovery of dwarf planet Eris was followed shortly by the discovery of its satellite, Dysnomia, but the satellite orbit, and thus the system mass, was not known. New observations with the Keck Observatory and the Hubble Space Telescopes show that Dysnomia has a circular orbit with a radius of 37,350 +/- 140 (1-sigma) kilometers and a 15.774 +/- 0.002 day orbital period around Eris. These orbital parameters agree with expectations for a satellite formed out of the orbiting debris left from a giant impact. The mass of Eris from these orbital parameters is 1.67 x 10(22) +/- 0.02 x 10(22) kilograms, or 1.27 +/- 0.02 that of Pluto.     

Enceladus: cosmic graffiti artist caught in the act

As one of the most geologically active bodies in the solar system, Saturn's moon Enceladus not only coats itself with water ice particles, it accounts for the unusually high albedos of the other satellites orbiting within Saturn's vast, tenuous E ring. This effect is evident in Hubble Space Telescope observations obtained at true opposition on 13 and 14 January 2005 that reveal that the mean geometric albedos of satellites embedded within the E ring approximate or exceed unity.     

Determination of Venus Winds by Ground-Based Radio Tracking of the VEGA Balloons

A global array of 20 radio observatories was used to measure the three-dimensional position and velocity of the two meteorological balloons that were injected into the equatorial region of the Venus atmosphere near Venus midnight by the VEGA spacecraft on 11 and 15 June 1985. Initial analysis of only radial velocities indicates that each balloon was blown westward about 11,500 kilometers (8,000 kilometers on the night side) by zonal winds with a mean speed of about 70 meters per second. Excursions of the data from a model of constant zonal velocity were generally less than 3 meters per second; however, a much larger variation was evident near the end of the flight of the second balloon. Consistent systematic trends in the residuals for both balloons indicate the possibility of a solar-fixed atmospheric feature. Rapid variations in balloon velocity were often detected within a single transmission (330 seconds); however, they may represent not only atmospheric motions but also self-induced aerodynamic motions of the balloon.     

Search for low-mass exoplanets by gravitational microlensing at high magnification

Observations of the gravitational microlensing event MOA 2003-BLG-32/OGLE 2003-BLG-219 are presented, for which the peak magnification was over 500, the highest yet reported. Continuous observations around the peak enabled a sensitive search for planets orbiting the lens star. No planets were detected. Planets 1.3 times heavier than Earth were excluded from more than 50% of the projected annular region from approximately 2.3 to 3.6 astronomical units surrounding the lens star, Uranus-mass planets were excluded from 0.9 to 8.7 astronomical units, and planets 1.3 times heavier than Saturn were excluded from 0.2 to 60 astronomical units. These are the largest regions of sensitivity yet achieved in searches for extrasolar planets orbiting any star.     

Infrared images of jupiter at 5-micrometer wavelength during the voyager 1 encounter

A coordinated program to observe Jupiter at high spatial resolution in the 5-micrometer wavelength region was undertaken to support Voyager 1 imaging and infrared radiation experiment targeting. Jupiter was observed over a 5-month period from Palomar and Mauna Kea observatories. The frequency of observations allowed the selection of interesting areas for closer Voyager examination and also provided good short-term monitoring of variations in cloud morphology. Significant global changes in the 5-micrometer distribution are seen over this time period.     

黑龙江省大豆不同生育阶段适宜温度与降水量化指标研究

利用黑龙江省7个具有代表性农业气象观测站1981~2014年大豆不同生育阶段逐日气温、逐日降水量、≥10℃有效积温、10 cm地温、密度、产量以及发育天数指标,统计分析黑龙江大豆不同生育阶段适宜温度与降水量。结果表明,黑龙江大豆播种至出苗期适宜10 cm地温为8℃;出苗至开花期适宜平均气温为18~22℃,适宜平均降水量为70~145 mm;开花至结荚期适宜平均气温为19~25℃,适宜平均降水量为70~120 mm;结荚至成熟期适宜平均气温为15~21℃,适宜平均降水量为110~185 mm。     

Laser ranging retro-reflector: continuing measurements and expected results

After successful acquisition in August of reflected ruby laser pulses from the Apollo 11 laser ranging retro-reflector (LRRR) with the telescopes at the Lick and McDonald observatories, repeated measurements of the round-trip travel time of light have been made from the McDonald Observatory in September with an equivalent range precision of +/-2.5 meters. These acquisition period observations demonstrated the performance of the LRRR through lunar night and during sunlit conditions on the moon. Instrumentation activated at the McDonald Observatory in October has yielded a precision of +/-0.3 meter, and improvement to +/-0.15 meter is expected shortly. Continued monitoring of the changes in the earth-moon distance as measured by the round-trip travel time of light from suitably distributed earth stations is expected to contribute to our knowledge of the earth-moon system.     

X-ray line and continuum spectra of solar flares from 0.5 to 8.5 angstroms

Two crystal spectrometers aboard the orbiting solar observatory OSO-4 cover the wavelength ranges 0.5 to 3.9 angstroms and 1.0 to 8.5 angstroms. Within this range, there appear emission lines from hydrogen-like and helium-like states of calcium, sulfur, silicon, magnesium, and aluminum. The Mg XII Lyman-alpha is present strongly in all x-ray flares. The most intense flares (such as class 3) produce strong Si XIV Lyman-alpha and often S XVI Lyman-alpha. Emission, in the form of Ka lines of highly ionized states of calcium, iron, aluminum, and silicon is usually present. The continuum from 1 to 10 angstroms always dominates the line emission by more than an order of magnitude. Electron temperatures derived from the slope of the continuum spectrum are in the range of 10(7) to 10(8) degrees K, considerably higher than theoretical ionization equilibrium temperatures.